1. Field of the Invention
Embodiments of the invention generally relate to a gripping apparatus for supporting tubulars. In particular, embodiments of the invention relate to a gripping apparatus disposable within a rotary table and having a slip assembly for gripping tubulars that is operable using a leveling ring. Additional embodiments of the invention relate to a control line guide assembly for protecting control lines in use with the supported tubulars.
2. Description of the Related Art
The handling of pipe strings has traditionally been performed with the aid of a spider. Typically, spiders include a plurality of slips circumferentially surrounding the exterior of the pipe string. The slips are housed in what is commonly referred to as a “bowl.” The bowl is regarded to be the surfaces on the inner bore of the spider. The inner sides of the slips usually carry teeth formed on hard metal dies for engaging the pipe string. The exterior surface of the slips and the interior surface of the bowl have opposing engaging surfaces which are inclined and downwardly converging. The inclined surfaces allow the slips to move vertically and radially relative to the bowl. In effect, the inclined surfaces serve as camming surfaces for engaging the slips with the pipe. Thus, when the weight of the pipe is transferred to the slips, the slips will move downwardly with respect to the bowl. As the slips move downward along the inclined surfaces, the inclined surfaces urge the slips to move radially inward to engage the pipe. In this respect, this feature of the spider is referred to as “self tightening.” Further, the slips are designed to prohibit release of the pipe string until the pipe load is supported by another means.
Traditionally, a spider is located above a rotary table situated in the rig floor. More recently, flush mounted spiders have been developed so that the spider does not intrude upon the work deck above the rotary. Because flush mounted spiders reside within the rotary table, the pipe size handling capacity of the spider is limited by the size of the rotary table. Current spider designs further augment the problem of limited pipe size handling capacity. Thus, in order to handle a larger pipe size, a larger rotary table must be used. However, the process of replacing the existing rotary table is generally economically impractical.
This pipe size handling capacity problem has been further complicated with the advent of intelligent completion systems. Improvements in technology now allow wellbores to be equipped with sensors, gauges, and other electronic devices that can be used to monitor various wellbore characteristics such as temperature, pressure, flow rate, etc. Additionally, downhole tools can be controlled remotely from the well surface or at some other remote location. However, to communicate with such devices and tools, these intelligent systems require multiple control lines that are run from the well surface to these downhole components with the pipe string. Accommodations must be made to make sure that these control lines are not pinched or damaged by the setting of the slips during makeup or breakup of the pipe string.
Another problem of some spiders currently in use is that many pipe joints may include coatings, for example to prevent corrosion, requiring higher downward forces to ensure positive slip engagement with the pipe joints. Further, in many completion operations the maximum height of the spider is limited by a connection height due to the length of the pipe joints. Further still, the slips are generally held in position in the bowl by friction, resulting in a limited amount of torque that may be applied to the pipe joints before slippage occurs between the slips and the bowl.
There is a need, therefore, for an improved gripping apparatus to address and overcome the problems described above.